Free pump control system



1964 c. L. ENGLISH ETAL 3,

FREE PUMP CONTROL SYSTEM Filed Nov. 5,1962 2 Sheets-Sheet 1 INVENTORS 4CHAPLES L, fA m/lswf JOHN B: M/ooos Feb. 11, 1964 c. L. ENGLISH ETAL3,120,812

FREE PUMP CONTROL SYSTEM Filed Nov. 5, 1962, 2 Sheets-Sheet 2 3' I EHEQM8 doH/v 5: W000;

Fi -E y United States Patent This invention relates generally toimprovements in valves, and more particularly, but not by way oflimitation, to an improved control system for a subsurface hydraulicpump installation.

As it is well known in the production division of the oil industry,subsurface hydraulic pumps are being used more and more for removing oilfrom wells which have ceased to produce by natural gas pressure. Thereare basically two types of subsurface hydraulic pump installations. Inone type of installation, known as the insert type, the subsurfacehydraulic pump is secured on the lower end of a tubing which requiresthe complete removal of either one or two strings of tubing when thesubsurface pump requires replacement or repair.

The second and perhaps most popular subsurface pump installation is whatis known as the free pump type. In this type of system, one relativelylarge string of tubing and one smaller string of tubing are installed inthe well and interconnected at their lower ends. The subsurfacehydraulic pump is of a size to move through the larger string of tubingin the nature of a piston when high pressure fluid is imposed on theupper end of the large string. The pump is in operating position whenseated at the lower end of the large string of tubing. The pump isremoved from the well by imposing high pressure fluid on the smallstring of tubing which forces the subsurface pump upwardly through thelarge string, again in the nature of a piston. When seated at the lowerend of the large string of tubing, the pump may be operated by highpressure power fluid being forced downwardly through either the largestring or the small string, depending upon whether the pump is latchedinto position when seated at the lower end of the large string. Ineither event, the exhausting power fluid and a volume of well fluid arepumped upwardly through the other tubing to the surface for storage andtreatment. It will thus be seen that a valving or control system must beprovided at the well head for feeding high pressure power fluid intoeither the large string or the small string, and for directing fluidfrom either of the tubing strings to storage facilities. The requiredcontrol system must therefore provide what may be considered a four-wayvalving action.

Prior to the present invention, there have been two basic types ofcontrol systems used in industry. One type of control system uses afour-way, tapered plug-type valve which is unduly sensitive to pressurevariations in the high pressure power fluid and is difficult to sealagainst the extremely high pressures of the power fluid. The second typeof control system utilizes a pair of threeway valves requiring the useof four valve seats which are, of course, subject to wear and requirefrequent repair, since the valves are handling abrasive fluids.

The present invention contemplates a novel control system wherein thevalve structure which is subject to abrasive fluids requires only twovalve seats. In a preferred embodiment, the valve structure utilizes twoballtype valves and ball valve seats which are the most economical anddurable type of construction for abrasive fluid service. In addition tothe valve structure referred to, the present control system requireseither a pair of hand-operated one-way valves, or a single three-wayvalve, but these valves are subjected only to clean power oil and willhave long and trouble-free service lives. The flow of fluid to and fromthe large and smaller strings "ice of tubing is accomplished simply byclosing one handoperated valve and opening another hand-operated valve.

The present invention also contemplates a control system wherein thepressure of the power fluid being fed to either the large string or thesmall string of tubing will be automatically indicated, such that theoperator of the system will be constantly advised of the condition ofthe system. The pressure indication is obtained by a valve assemblyhaving one end connected to the large string of tubing and the other endconnected to the small string of tubing. A simple ball valve movesbetween a pair of spaced valve seats when the pressure at the oppositeends of the valve assembly varies, whereby the higher pressure isadmitted to the central portion of the valve assembly. The centralportion of the valve assembly is connected to a pressure gauge in viewof the operator of the system.

An object of this invention is to provide a control system for a freepump installation wherein the valve structure exposed to abrasive fluidsutilizes the minimum number of valve seats.

Another object of this invention is to provide such a control systemwherein the valve structure exposed to the abrasive fluids utilizes themost durable and economical valve seat and valve member constructions.

Another object of this invention is to provide a control system for thelarge and smaller strings of tubing of a free pump installation whereinthe flow of fluid to and from the large and small strings of tubing maybe controlled by simply operating a single three-way valve, for byclosing one manual valve and opening another manual valve.

A further object of this invention is to provide a free pump controlsystem wherein the fluid discharged from the larger string of tubing ofthe installation during removal of the subsurface pump will be directedinto storage facilities or the like and will not be turned loose at thewell head.

Another object of this invention is to provide a free pump controlsystem wherein the highest pressure being imposed on either the largestring or the small string of tubing of the pump installation will beautomatically indicated for the operator of the system.

A still further object of this invention is to provide a free pumpcontrol system utilizing the maximum of conventional parts; which may beeconomically manufactured; which may be easily repaired and which may beeasily operated by unskilled workmen.

Other objects and advantages of the invention will be evident from thefollowing detailed description when read in conjunction with theaccompanying drawings which illustrate our invention.

In the drawings:

FTGURE 1 is an elevational view of a subsurface hydraulic pumpinstallation utilizing our novel control system, with portion of thepump installation being shown in section.

FIGURE 2 is an elevational View of a portion of the control system asviewed at the side opposite that shown in FIG. 1.

FIGURE 2A is an enlarged sectional view showing the connection of thesmall tubing to the valve body.

FIGURE 3 is a top view of a portion of the control system shown in FIGS.1 and 2.

FIGURE 4 is a side elevational view of the valve body of the controlsystem with the various couplings removed and with a portion of thepassageways in the body being shown in dashed lines.

FIGURE 5 is a cross sectional view taken along lines 55 of PEG. 4illustrating the details of construction of the pressure-measuring valveassembly.

FIGURE 6 is a sectional view taken along lines 6-6 3 of FIG. 4illustrating the details of construction of the pressure-measuring valveassembly.

Referring to the drawings in detail, and particularly FIG. 1, referencecharacter id generally designates the control system of this inventionconnected to the upper ends of a large string of tubing 12 and a smallerstring of tubing 14. The tubhig strings l2 and 14 extend in parallelrelation through a wellbore (not shown) and are interconnected at theirlower ends 16 and 18 in any suitable manner to provide communicationbetween the tubing strings. A seating shoe 2GB is normally positioned inthe extreme lower end of the large string of tubing 12 and communicateswith the wellbore through a Well fluid inlet 22 formed in the extremelower end of the large tubing string. A suitable subsurface hydraulicpump 24 of the free type is seated in the shoe 20 and extends upwardlyin the large tubing string 12 in its normal pumping position. The pump 2may be of the type to receive power oil through the smaller tubing 14and exhaust a combination of exhausted power fluid and well fluidupwardly through the large tubing 12 if desired. However, for simplicityof illustration and explanation, it will be assumed that the pump 24 isof a type to receive power oil at its upper end from the large tubing 12and to pump the exhausted power fluid and well fluid upwardly throughthe smaller tubing 14. It will be noted that downwardly facing cups 26are provided on the upper end of the pump 24 for use in pumping the pump24 upwardly through the large tubing 12, as will be described in detailbelow. Also, intermediate seals 28 are normally provided along thecentral portion of the pump 24 to separate the power oil and exhaustingfluids flowing to and from the pump 24 in the conventional manner.

The control system It comprises a valve body 30 (the details of whichwill be described below) having two inlet lines 32 and 34 suitablysecured to the opposite sides of the valve body 3%) by couplings 36. Theinlet lines 32 and 34 extend in parallel from a common power fluidsupply line 38 suitably connected (not shown) to a source of highpressure power fluid. The power fluid is normally clean oil. The flow ofthe high pres sure power fluid from the supply line 38 to the inletlines 32 and 34 is controlled by a manually operated oneway valve 4interposed in the inlet line 32 and a manually operated one-Way valve 42interposed in the inlet line 34-. The valves 4i? and 42 will be or"conventional construction. It will also be understood that the twovalves 4% and 42 may be replaced by a single threeway valve at theconnection of the line 38 to the lines 32 and 3 if desired.

An outlet line 44 extends from the front of the valve body 30 to directthe fluid flowing from either the large tubing 12 or the smaller tubing14 to suitable storage facilities (not shown). Another hand-operatedvalve 46 is preferably interposed in the outlet line 44 in the event itis desired to completely close in the installation. The valve 46 Will beopen during all normal operations of the control system 10. it is alsodesirable to provide a bypass line 4% connecting the power fluid line 58to the outlet line 44 downstream of the valve 46 in the event it isdesired to circulate power oil from the power oil source to storagefacilities. A manually operated valve 59 is interposed in the bypassline 43 and is closed'during all normal operations of the control systemit).

The control system ill also includes a pressure gauge 52 mounted on thetop of the valve body 3t) and connected to register the highest pressureexistin. in either the large tubing 12 or the small tubing 14, as willbe described in the detailed description of the valve body 3%). Also, asuitable pump catcher 54 is mounted on the top of the valve body Si? incommunication with the large tubing string 12 to receive and hold thepump 24 when the pump 24 is removed for repair or replacement, as willbe described below.

The details of construction of the valve body 30 are illustrated inFIGS. 4 through 6. As shown in FIG. 5, a bore or passage 56 is formedall the way through the valve body 3d from one side 58 to the oppositeside 60 and communicates at its opposite ends with the inlet lines 32and 34. An outlet port or bore 62 extends from the back 64 of the valvebody 3% and intersects the central portion 66 of the passage 56. A largebore 68 is formed vertically all the way through the valve body 3%forwardly of the passage 56 for connection at its lower end with thelarge tubing string 12 and for connection at its upper end with the pumpcatcher 54 previously described in connection with FIG. 1. The largebore 68 communicates with one end portion 76 of the passage as by acut-away portion 72 formed in the valve body 3d at the level of thepassage 56. It may also be noted that the cut-away portion 72 ispositioned above the upper end of the large tubing string 12 and belowthe lower end of the pump catcher 54 to provide constant communicationbetween the bore 68 and the end portion '70 of the passage 56. Anothervertical bore 74 is formed from the bottom of the valve body 3t}forwardly of the passage 56 and extends upwardly in the valve body 30 tothe level of the passage 56. The bore 74 is provided to connect with thesmaller tubing string 14. Another horizontal bore '76 extends from thefront 78 of the valve body 3 to the end portion 30 of the passage 55 andintersects the upper end portion of the bore '74 to provide constantcommunication between the smaller tubing string 14 and the end portion80 of the passage 56. The extreme forward end of the horizontal bore '76is provided With a bleed valve 82 (FIG. 3) for purposes to be described,but it may be noted that the bleed valve 82 is normally closed.

A novel shuttle valve is positioned in the passage 56 to control theflow of fluid to and from the tubing strings 12 and 14 in response todifferent pressures applied at the inlet lines 32 and 34. The shuttlevalve 84 comprises a pair of ball valve seats 86 and 88 positioned onopposite sides of the central portion 66 of the passage 56, that is, onopposite sides of where the outlet port 62 intersects the passage 56.Each of the valve seats do and 88 is sealed in the passage 56 by asuitable O-ring 9t) and is held against an outwardly facing shoulder 92by a liner 94. Each liner M is reduced in diameter from its outer end toapproximately the middle of the liner to assist in operation of theshuttle valve 84 as will be described. The outwardly facing shoulders 92are formed either by a variation in the diameter of the passage 56 or bya separate spacer, and the liners 94 are retained in the passage 56 bythe inlet lines 32 and 34, or by the couplings 36 used to connect theinlet lines 32 and 34 to the valve body. However, the liners 94 arepreferably loosely fitted in the pas sage 56 to minimize the strengthrequired. The liners 94 are held against the seats 36 and 88 by pressureon the shuttle valve, as will be described. It will also be noted thateach liner 94 is provided with a plurality of circumferentially spacedslots 96 to provide substantially unrestricted flow of fluid from thepassageway 56 to and from the tubing strings 12 and 14. The valve seats86 and are provided with outwardly facing seatingareas 9d and ltltl andare preferably provided with similar seating areas on the opposite sidesthereof in order that the valve seats may be installed in eitherdirection and may be reversed when the seating areas become Worn.

A ball valve 652 is positioned in the passage 56 outwardly of the valveseat 86, and another ball valve N4 is positioned in the passage 56outwardly of the valve seat 8% to cooperate with the seating areas andTilt respectively. The ball valves Hi2 and tea are sized to a slidingfit in the outer end portions of the respective liners 94 and areretained in spaced relation at a distance greater than the spacingbetween the valve seats 86 and 83 by a spacer member 1%. The spacer 166is preferably in the form of a tube shaped at its opposite ends tocontact the ball valves 1G2 and 1634 without damaging the ball valves.The spacer 11% has an outer diameter of a size for a sliding fit of thespacer in the valve seats 86 and 88 so that the spacer will notinterfere with the movements of the ball valves M92 and 1594. It willalso be noted that the spacer res has two sets of circumferentiallyspaced slots 1% in order that the spacer will not materially restrictthe flow of fluid through the passageway as in any operating position ofthe spacer. Each set of slots 1% is of a length substantiallycorresponding to the spacing between the valve seats 36 and 88 tominimize the restriction of fluid flow in the passageway 56 and yetleave suflicient material in the spacer 1% for the strength required tounseat the ball valves M2 and illi.

The operation of the shuttle valve 184 may be determined from anexamination of FIG. 5. When high pressure power fluid is being fed tovalve body 35 through the inlet line 32, and is not being fed throughthe inlet line 34, the high pressure fluid in the end portion 7% of thepassage 56 acts on the ball valve ill-i to move the valves to the leftand seat the ball valve l vid on the seating area lit-t9 of the valveseat 88 In this position of the shuttle valve, the high pressure powerfluid flows through the slots 96 in the right-hand liner 94, and throughthe cutaway portion '72 into the large vertical bore 68 for passagedownwardly into the large tubing string 12. On the other hand, any fluidflowing upwardly through the smaller tubing string 14 at this time willflow upwardly through the smaller vertical bore 7%, rearwardly throughthe horizontal bore 76 and then through the slots 96 in the lefthandliner 9% and the left-hand slots 1% in the spacer 106 into the endportion of the passage as. The fluid then has free passage through thecentral portion at of the passage 56, rearwardly through the right-handslots 1&8 in the spacer and then through the discharge port or outletport as and outlet line 44.

When the pressure differential across the shuttle valve 84 is reversed,by imposing power fluid pressure in the inlet line 34 ind cutting offpower fluid pressure in the inlet line 32, the high pressure fluidacting on the ball valve 192 will move the ball valves to the right andseat the ball valve M2 on the seating area 93 of the valve seat 36. Itwill also be noted that each ball valve iits fairly closely in therespective liner 9-4 when the respective ball valve is in the outer endof the liner. Thus, when the ball valves are positioned as shown in FIG.5, the pressure in inlet line acts across the entire cross sectionalarea of ball valve 152; whereas, the pressure in inlet 32 acts on ballvalve res only across the area of the seat 1%. Thus, even though thepressures in the inlet lines 32 and 34 are equal, the shuttle valve willstart moving to the right. When the pressure in inlet 32 is decreased bya bleedofi to outlet line the ball valve will become seated on seat 86.It will then be apparent that the high pressure fluid may flow from theinlet line 3 through the end portion of the passage 56 and through thebore 76 and the bore '74 downwardly into the through the smaller tubingstring 14. On the other hand, any fluid flowing upwardly in the largetubing string 12 will be discharged through the bore 68, cut-awayportion 72, end portion 74} of passage ss, central portion 66 of passage56 and outwardly through outlet port 62 and outlet line 44. Thisreversal of fluid flow to and from the tubing strings l2 and 14 isobtained for insertion, operation and removal of the subsurfacehydraulic pump 24 as will be descri ed below. As also shown in FIG. 5,each of the inlet line couplings as may be provided with a counterboreat its inner end to partially receive the ball valves 2 and R4 to reducethe required overall width of the valve body 3%.

The structure utilized for registering the pressure in the tubingstrings l2 and 14- by the pressure gauge 52 is illustrated in FEGS. 4and 6. A horizontal bore 12% is formed from the side 58 of the valvebody 3t) (FIG. 6)

above and parallel with the passage 56 previously described inconnection with FIG. 5. An outwardly facing shoulder 122 is formed inthe medial portion of the bore to receive and support a ball valve seat124. A second ball valve seat 126 is retained in spaced relation in thebore 12% from the seat 124 by a perforated spacer 128 having an outerdiameter smaller than the diameter of the respective portion of the bore12% The seat 126 is in turn held by a plug 139 threadedly secured in theouter end of the bore 1129. It will also be noted that the plug 139 isreduced in diameter near its inner end 132 and is provided with apartial bore 134 in its inner end which communicates with the bore 12dthrough radially extending ports or apertures 136. Both of the seats 12dand 126 are sealed in the bore 12-13 by suitable 0- rings 13%. A ballvalve 14b is positioned in the spacer 128 and is of a size to rollfreely in the spacer 123 into seating engagement with either of theseats 124- or 12-25 in response to pressure differentials in the seats124 and 126, as will be described.

One vertical bore 142 is drilled from the top 144 of the valve body 39downwardly in intersecting relation wtih the inner end portion M6 of thebore 1% and into communication with the end portion 7d of the passage56. it will be noted here that this end portion 79 of the passage So isin constant communication with the large tubing string 12 as previouslydescribed in connection with FIG. 5. The upper end of the bore 142 isclosed by a plug 147. Another vertical bore 148 is drilled from the topl idof the valve body in intersecting relation with the bore 12 at thelocation of the inner end portion 132 of the plug 1% and extends ondownwardly into communication with the end portion 83 of the passage aspreviously described. The upper end of the bore 143 is closed by a plugM9. it will again be noted that the end portion 89 of the passage 56 isin constant communication with the smaller tubing string 14 aspreviously described in connection with FIG. 5. Thus, the pressure inthe large tubing string 12 is constantly transmitted through the bore142 and the right-hand valve seat 124 to act on the right-hand side ofthe ball valve 149; Whereas, the pressure in the smaller tubing string14- is constantly transmitted through the bore 14-8 and the valve seat12s against the left-hand side of the ball valve 14%). it will thereforebe apparent that the ball valve 141? will be moved to the low pressureside and close oil the valve seat 124 or 126 subjected to the lowestpressure. The higher pressure imposed on the ball valve Mil will beexerted through the ported spacer 123. This higher pressure istransmitted to the pressure gauge 52 through a horizontal bore 156) (seeFIG. 4) drilled in the body 3i? from the rear face 64 of the valve body,and then upwardly through a vertical bore 152 which intersects the bore159. The pressure gauge 52, is threadedly secured in the upper endportion of the vertical bore i512. It will be understood that the outerend of the bore T54) is closed by a plug 153 to prevent leakage from thevalve body 30.

Another important practical feature of the present control system is theconnection of the small tubing string 14 to the valve head asillustrated in FIG. 2A. As shown, an adapter 16% is threadedly securedin the lower end of the body 3% at the lower end of the vertical bore'74 described in connection with PEG. 5. A tubular mandrel 162 isslip-fitted in the lower end of the adapter 16%) and is sealed thereinby a suitable O-ring 164. The mandrel 162 is held in the desiredposition in the adapter lot) by a tapered locking ring or collar 166threadedly secured around the lower end of the adapter 169. The taperedface 168 of the collar lied cooperates with a cor respondingly taperedportion 179 on the lower end of the adapter 16% to provide a wedgingaction when the collar is threaded tight to provide a friction grip ofthe adapter res around the mandrel 162. The mandrel 162 has an offset172 near its lower end to threadedly receive the upper end of the tubingstring 14-. It will thus be apparent that the mandrel is; may be turnedin any desired direction to vary the spacing between the small tubingstring 14 and the large tubing string 1?; to accommodate substantiallyany existing subsurface pump installation.

Operation Prior to installation of the pump 24- into operating positionas illustrated in FIG. 1, let it be assumed that the normal valve in theseating shoe 20 is closed and the tubing strings l2 and 1-: are full ofoil, as will normally be the case. It will also be observed that themanual valves 4%) and 42 will be closed when the pump 24 is removed. Thepump 2d is inserted in the upper end of the large tubing strings 12. byremoving the pump catcher 5d and simply droppin the pump into the largetubing; whereupon the tubing catcher 54 is replaced. The manual valve isthen opened to direct the high pressure power fluid through the inletline 32. This high pressure fluid acts on the ball valves 1G4 and 102 tothe positions shown in FIG. 5. As previously described, the highpressure power fluid then flows downwardly through the tubing string 12and forces the pump 24 downwardly through the tubing string l2 until itbecomes seated on the seating shoe 243* as illustrated in PEG. 1. Duringthe downward movement of the pump 24, the fluid below the pump is forcedupwardly through the smaller tubing string 14 where it enters thevertical bore 7d of the valve body 3%). As previously described, thisfluid then flows through the bore '76, the end portion till of thepassage 56, the central portion 66 of the passage 55, and out throughthe outlet port 62 and outlet line 44 to the storage facilities.

When the pump 24 is seated as illustrated in FIG. 1, the high pressurepower fluid is continually fed from the inlet line 32 downwardly throughthe tubing string v1:2 to operate the pump. The exhausting power fluidand pumped well fluid drawn in through the inlet 22 at the lower end ofthe installation are forced upwardly through the smaller tubing string14 and discharged through the outlet line 44 to storage. While the highpressure power fluid is being directed through the large tubing string12, the pressure of this fluid will be exerted through the valve seat124 (FIG. 6) to move the small ball valve 14b to the left against theseat 126, such that this pressure will be applied on the pressure gauge52 to advise the operator of the system of the highest pressure beingimposed on the pump installation.

When it is desired to remove the pump 24 for replacement or repair, themanual valve 42 (FIG. 1) is opened and the valve 49 is closed. It willthen be observed that the high pressure power fluid is fed through theinlet line 34- to react on the ball valve 162 of the shuttle valveassembly. The ball valves M2. and 1M are therefore moved to the right(with respect to FIG. 5) to seat the ball valve 1% on the valve seat 86.As previously described, the high pressure power fluid is then directeddownwardly through the smaller tubing string 14, and the large tubingstring 12 is opened to the outlet line &4. The high pressure power fluidflowing downwardly through the small tubing string 14 will first reacton the intermediate seals 23 of the pump unit 24- and unseat the pump;whereupon this high pressure fluid flows upwardly through the largetubing string 12 and reacts on the downwardly facing cups 26 to move thepump 24 upwardly through the large tubing string l2. This operation iscontinued until the upper end of the pump 24 enters and is engaged bythe pump catcher 5d; whereupon the bypass valve 5b is opened to protectthe power fluid source. The valve 423 and the valve as are closed. Also,to relieve any pressure existing in the tubing strings l2 and 14, thebleed valve 82, is opened; whereupon the pump catcher 54 may be safelyremoved to remove the pump 24. It will also be noted that when highpressure power fluid is being applied to the smaller tubing string t4,the pressure of this fluid is transmitted through the valve seat (FIG.6) to move the small ball valve lldii to the right against the valveseat lZd. Thus, the pressure of the high pressure power fluid is thenapplied to the pressure gauge 52 to again advise the operator of thesystem of the highest pressure being applied to the pump installation.

From the foregoing, it will be apparent that the present inventionprovides a highly useful and simply operated control system for freepump installations. The only valve structure utilized in the systemwhich is subjected to the abrasive well fluids comprises ball-typevalves and ball valve seats which are historically the least subject towear by abrasive fluids. Also, only two valve seats are used in theabrasive fluid environment to minimize the parts subject to wear.Further, these two valve seats are reversible for convenience in repair.The entire control system utilizes the maximum of standard andcommercially available parts to provide an economical construction. Thehighest pressure being applied to the free pump installation isconstantly indicated, regardless of whether the high pressure is beingapplied to the large string or the small string. It will also beapparent that the present control system may be installed onsubstantially any existing free pump installation, regardless ofvariations in the spacings between the large and small tubing strings.

Changes may be made in the combination and arrangement of parts orelements as heretofore set forth in the specification and shown in thedrawings, it being understood that changes may be made without departingfrom the spirit and scope of the invention as defined in the followingclaims.

We claim:

1. A control system for a free pump installation, including a largetubing string and a small tubing string positioned in a well andconnected at their lower ends, a pump in the large tubing string, and asource of high pressure power fluid for operating the pump, comprising:

a valve body having a first passage therethrough and an outlet passageintersecting the central portion of the first passage;

means forming an outwardly facing valve seat in the rst passage at eachside of the outlet passage; means connecting the large tubing string tothe first passage between one valve seat and the adjacent end of thefirst passage; means connecting the smaller tubing string to the firstpassage between the other valve seat and the adjacent end of the firstpassage;

hand-operated valve means connecting the source of high pressure fluidto the opposite ends of the first passage for feeding the high pressurefluid into either end of the first passage; and

a shuttle valve in the first passage responsive to pressures on theopposite ends thereof for alternately seating on the valve seats tosimultaneously provide communication between the large tubing string andthe outlet passage and between one end of the first passage and thesmaller tubing string for removing the pump through the large tubingstring, and, alternately, simultaneously provide communication betweenthe small tubing string and the outlet passageway and between the otherend of the firstpassage and the larger tubing string for inserting thepump in the well through the large tubing string.

2. A system as defined in claim 1 wherein said shuttle valve comprises apair of ball valves on opposite sides of the valve seats, and a spacerextending through the valve seats retaining the ball valves a distanceapart greater than the distance between the valve seats, whereby onevalve seat is always open for the flow of the fluid into the outletpassage.

3. A system as defined in claim 2 wherein said spacer comprises a sleevehaving openings in the Walls thereof for flow between either one of saidtubing strings and the outlet passage.

4. A system as defined in claim 3 wherein said sleeve is separate fromthe ball valves.

5. A system as defined in claim 2 characterized further to include aslotted liner in said first passage on the outer side of each valve seatreceiving the respective ball valve, each liner having a variable innerdiameter to restrict the flow of fluid around the respective ball valvewhen the other ball valve is on its seat, whereby both ball valves willbe unseated when equal pressures are applied to the opposite ends ofsaid first passage.

6. A system as defined in claim 2 wherein said valve seats are removableand characterized further to include a slotted liner in the firstpassageway on the outer side of each valve seat to support therespective ball valve and providing communication between the firstpassageway and the respective tubing string, each of said liners havinga decreased inner diameter near the outer end thereof.

7. In a tree pump system, including a large tubing string and a smalltubing string positioned in a well and connected at their lower ends, apump in the large tubing string, and a source of high pressure powerfluid for operating the pump, the improvement comprising:

a valve body connected to both the large and small tubing strings andhaving a pair of power fluid inlets, said body also having an outletport;

manual valve means connecting the source of high pressure power fluid toboth of said inlets for alternately feeding high pressure power fiuid tosaid inlets;

valve means in the valve body for connecting one inlet to the smallertubing and the large tubing to the exhaust port while power fluid isbeing fed to said one inlet and, alternately, connecting the other inletto the larger tubing string and connecting the smaller tubing string tothe exhaust port while high pressure power fluid is being fed to saidother inlet;

a pressure-measuring bore in the valve body having a first end and asecond end;

means connecting the first end of the pressure bore to the smallertubing string;

means connecting the second end of the pressure bore to the largertubing string;

a pressure gauge;

means connecting the central portion of the pressure bore to thepressure guage; and

second valve means in the pressure bore providing communication onlybetween the central portion of the pressure bore and the end of thepressure bore having the highest pressure.

8. A system as defined in claim 7 wherein said second valve meanscomprises a valve seat in the pressure bore on each side or" saidcentral portion of the pressure bore, a slotted liner between said valveseats, and a ball valve loosely disposed in said liner, said ball valvebeing of a size to seat on either of said valve seats.

9. A control system for a free pump installation, ineluding a largetubing string and a small tubing string positioned in a well andconnected at their lower ends, a pump in the large tubing string, and asource of high pressure power fluid for operating the pump, comprising:

a valve body having a first passage therethrough and an outlet passageintersecting the central portion of the first passage;

means forming an outwardly facing valve seat in the first passage ateach side of the outlet passage;

means connecting the larger tubing string to the first passage betweenone valve seat and the adjacent end of the first passage;

means connecting the smaller tubing string to the first passage betweenthe other valve seat and the adjacent end of the first passage;

hand-operated valves connecting the source of high pressure fluid to theopposite ends of the first passage for feeding the high pressure fluidinto either end of the first passage;

a shuttle valve in the first passage responsive to differentialpressures on the opposite ends thereof for controlling the fiow of fluidto and from the large and small tubing strings;

a pressure-measuring bore in the valve body having a first end and asecond end;

means connecting the first end of the pressure bore to the smallertubing string;

means connecting the second end of the pressure bore to the largertubing string;

a pressure gauge;

means connecting the central portion of the pressure bore to thepressure gauge; and

second valve means in the pressure bore providing communication onlybetween the central portion of the pressure bore and the end of thepressure bore having the highest pressure.

10. A system as defined in claim 9 wherein said second valve meanscomprises a valve seat in the pressure bore on each side of theconnection or" the pressure bore to the pressure gauge, a slotted linerbetween said valve seats, and a ball valve slidingly disposed in saidliner, said ball valve being of a size to seat on either of said valveseats.

11. A control system for a free pump installation, including a largetubing string and a smaller tubing string positioned in a well andconnected at the lower ends, a pump in the large tubing string, and asource of high pressure power fluid for operating the pump, comprising:

a valve body connected to the larger tubing, the smaller tubing and thesource of high pressure power fluid;

valve means in the valve body controlling the flow of high pressurepower fluid to the smaller tubing, and, alternately, the larger tubingfor insertion, operation and removal of a pump from the larger tubing;

a pressure-measuring bore in the valve body having a first end and asecond end;

means connecting the first end of the pressure bore to the smallertubing;

means connecting the second end of the pressure bore to the largertubing;

a pressure gauge;

means connecting the central portion of the pressure bore to thepressure gauge; and

second valve means in the pressure bore providing communication onlybetween the central portion of the pressure bore and the end of thepressure bore having the highest pressure.

References Cited in the file of this patent UNITED STATES PATENTS1,993,292 Woods Mar. 3, 1935

1. A CONTROL SYSTEM FOR A FREE PUMP INSTALLATION, INCLUDING A LARGETUBING STRING AND A SMALL TUBING STRING POSITIONED IN A WELL ANDCONNECTED AT THEIR LOWER ENDS, A PUMP IN THE LARGE TUBING STRING, AND ASOURCE OF HIGH PRESSURE POWER FLUID FOR OPERATING THE PUMP, COMPRISING:A VALVE BODY HAVING A FIRST PASSAGE THERETHROUGH AND AN OUTLET PASSAGEINTERSECTING THE CENTRAL PORTION OF THE FIRST PASSAGE; MEANS FORMING ANOUTWARDLY FACING VALVE SEAT IN THE FIRST PASSAGE AT EACH SIDE OF THEOUTLET PASSAGE; MEANS CONNECTING THE LARGE TUBING STRING TO THE FIRSTPASSAGE BETWEEN ONE VALVE SEAT AND THE ADJACENT END OF THE FIRSTPASSAGE; MEANS CONNECTING THE SMALLER TUBING STRING TO THE FIRST PASSAGEBETWEEN THE OTHER VALVE SEAT AND THE ADJACENT END OF THE FIRST PASSAGE;HAND-OPERATED VALVE MEANS CONNECTING THE SOURCE OF HIGH PRESSURE FLUIDTO THE OPPOSITE ENDS OF THE FIRST PASSAGE FOR FEEDING THE HIGH PRESSUREFLUID INTO EITHER END OF THE FIRST PASSAGE; AND A SHUTTLE VALVE IN THEFIRST PASSAGE RESPONSIVE TO PRESSURES ON THE OPPOSITE ENDS THEREOF FORALTERNATELY SEATING ON THE VALVE SEATS TO SIMULTANEOUSLY PROVIDECOMMUNICATION BETWEEN THE LARGE TUBING STRING AND THE OUTLET PASSAGE ANDBETWEEN ONE END OF THE FIRST PASSAGE AND THE SMALLER TUBING STRING FORREMOVING THE PUMP THROUGH THE LARGE TUBING STRING, AND, ALTERNATELY,SIMULTANEOUSLY PROVIDE COMMUNICATION BETWEEN THE SMALL TUBING STRING ANDTHE OUTLET PASSAGEWAY AND BETWEEN THE OTHER END OF THE FIRST PASSAGE ANDTHE LARGER TUBING STRING FOR INSERTING THE PUMP IN THE WELL THROUGH THELARGE TUBING STRING.